Pallet for transporting goods

ABSTRACT

A planar rectangular pallet  1  comprises fork entries  2  to admit two forks of a forklift on two sides  1   a,    1   b  (or four sides) thereof and a through hole  3  penetrating the sides  1   a   , 1   b  having the fork entries  2.  The through hole is located between the fork entries  2.  A non-contact IC tag (RFID tag  3 ) is provided inside the through hole  3  and in a vicinity of a middle portion in a length direction of the through hole.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2003-324860 filed in Japan on Sep. 17, 2003, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pallet for transporting goods and a pallet management system for managing the pallet.

2. Description of the Related Art

Pallets used for goods transportation and the like generally have the shape of a quadrangle (planar rectangle), and are provided with fork entries on sides thereof into which the fork of a forklift is inserted for transportation.

Examples of the above-described rectangular pallets include, for example, a two-way entry pallet which has two fork entries, into which two forks of a forklift can be inserted, on two sides (two opposite sides of a rectangle) of the sides (four sides) of the pallet, where the forks can be inserted into the pallet from two directions; and a four-way entry pallet which has fork entries on all the sides (four sides) of the pallet, where the forks can be inserted into the pallet from four directions.

Pallets used for goods transportation and the like may be carried in or out along with goods or products to be distributed, in order to facilitate transportation by a forklift. In this case, it is necessary to manage pallets which are transported into or out of a storage.

Conventionally, pallets which are transported into or out of a storage are managed by using slips. However, slips are likely to be lost during transportation in complex distribution pathways, and it is difficult to be aware of unauthorized use of pallets.

To avoid this, a management system has been proposed in, for example, JP 2003-11973A (hereinafter referred to as Patent Publication 1). In this management system, a PHS terminal or a positional information transmitting/receiving terminal is mounted on a pallet for transporting goods. By identifying a base station, which is receiving an electric wave from the PHS terminal or the positional information transmitting/receiving terminal, and calculating a distance from the base station, the current location of the pallet can be confirmed.

Another system has been proposed in, for example, JP 2003-36405A (hereinafter referred to as Patent Publication 2). In this system, information, such as the date and hour of collecting pallets (rental pallets), the number of collected pallets, or the like, is transmitted to a manager's terminal via a network, such as the Internet, bidirectional TV communication or the like, and a database of pallet information is constructed in a manager's server.

However, the system described in Patent Publication 1 is problematic in that it is difficult to secure a power source for the PHS terminal or the positional information transmitting/receiving terminal mounted on a pallet. For example, if the power of the terminal is 0, communication cannot be performed. Further, time and effort are required for charging the terminal. Furthermore, even when the location of a pallet is identified, it cannot be determined whether the pallet is effectively used or is missing. The system described in Patent Publication 2 also is problematic in that the requirement of entering information, such as the date and hour of collecting pallets, the number of collected pallets, or the like, is likely to lead to a situation in which the number of recorded pallets is inconsistent with the number of pallets which are actually transported into or out of a storage.

There is another management system, in which an ID tag is attached to a pallet and information is read/rewritten from/to the ID tag.

However, the antenna of an interrogator and the ID tag (transponder) need to face each other in order to read/rewrite information from/to the ID tag attached to the pallet. When a plurality of ID tags are attached to a pallet, information can be read from either of the ID tags. However, in order to write information into the ID tags, the ID tags need to be synchronized with one another (the ID tags need to have identical information). It is very difficult to realize this.

When only one ID tag is attached to a pallet on a side of the pallet, synchronization with other ID tags is no longer required. In this case, however, when trying to read the ID tag attached to the pallet from a side of the pallet opposite to the side on which the ID tag is attached, the pallet itself is an obstacle, so that information cannot be read/rewritten from/to the ID tag.

A technology for solving the above-described problem has been disclosed in, for example, JP 2002-240955A (hereinafter referred to as Patent Publication 3). In this technology, one ID tag (RF tag) can be detachably attached to a pallet side and the ID tag can be selectively provided on either one of two sides of the pallet. Another technology has been disclosed in, for example, JP H10-250730A (hereinafter referred to as Patent Publication 4). In this technology, an ID tag having an antenna is disposed along one diagonal line of a planar rectangular pallet, the antenna being erected.

However, in the above-described technology of Patent Publication 3, the ID tag needs to be attached to a pallet side that faces the antenna of an interrogator provided on a forklift, after confirming the location of the antenna. Therefore, the confirmation of the location of an antenna and the attachment of an ID tag are additionally required. In the technology of Patent Publication 4, the gain of the directional characteristics of the antenna is decreased, so that information may not be correctly read/rewritten.

SUMMARY OF THE INVENTION

In order to solve the above-described problems, the present invention provides a pallet for transporting goods, which has a non-contact IC tag capable of directly tracking a moving pathway or the like of a pallet, and in which information can be easily and reliably read/written from/to the non-contact IC tag by accessing it from either of the pallet sides (two sides for the two-way entry type; and four sides for the four-way entry type) on which fork entries are provided.

The goods transportation pallet of the present invention is in the shape of a planar rectangle and is provided with fork entries to admit two forks of a forklift. The fork entries are provided on two opposite sides of the pallet. The pallet is also provided with a through hole penetrating through the pallet from one to the other of the two sides having the fork entries (hereinafter also simply referred to as a through hole penetrating through the two sides). The through hole is located between the fork entries. A non-contact IC tag is provided inside the through hole and in the vicinity of the middle in the length direction of the through hole.

As described above, the pallet is provided with a through hole and a non-contact IC tag is placed inside the through hole. Therefore, the through hole is a kind of transmission pathway to the non-contact IC tag. A read signal or a rewrite signal transmitted by the antenna of an interrogator mounted on a forklift is propagated and transferred through the inside of the through hole to the non-contact IC tag. Thereby, it is possible to read/rewrite information from/to the non-contact IC tag from either of the two sides (or four sides) of the planar rectangular pallet.

In addition, a non-contact IC tag may be provided in a vicinity of a middle portion in a length direction of the through hole. In this case, information stored in the non-contact IC tag attached inside the through hole can be read unbiasedly and reliably from either of the two sides (or four sides) of the pallet. Also, information can be reliably rewritten.

In the pallet of the present invention, it is preferable that an inner surface of the through hole is covered with a conductive material.

In the pallet of the present invention, when a cross-section of the through hole is in the shape of a rectangle, the length of either side of the rectangular through hole should be equal to or larger than λ/2 where λ represents the wavelength of a frequency used between the non-contact IC tag and the interrogator.

Alternatively, when a cross-section of the through hole is in the shape of a circle, the radius of the rectangular through hole should be equal to or larger than λ/3.4 where λ represents the wavelength of a frequency used between the non-contact IC tag and the interrogator.

Further, when the through hole has a ridge-shaped cross-section, the length of a side or the radius of the through hole can be smaller than when the through hole has a rectangular or circular cross-section, where comparison is performed using the same frequency.

It is also preferable that a cross-section area of the through hole is increased from an inner portion of the pallet toward the sides of the pallet.

In the pallets of the present invention, a through hole may be provided in a vicinity of a middle portion of the pallet, and the through hole may intersect with the through hole penetrating through the sides and extend vertically with respect to the pallet.

An example of the non-contact tag attached to the pallet of the present invention is an RFID tag used in an RFID (Radio Frequency Identification) system. The non-contact IC tag (hereinafter referred to as an RFID tag) may store information about products/goods being transported, information about a truck which transports products/goods, identification information about a pallet itself, or the like.

The pallet of the present invention is provided with a through hole penetrating through sides of the pallet and a non-contact IC tag (e.g., an RFID tag, etc.) attached inside the through hole. Therefore, the through hole is a kind of transmission pathway to the non-contact IC tag. A read signal or a rewrite signal transmitted from the antenna of an interrogator mounted on a forklift is propagated and transferred through the inside of the through hole to the non-contact IC tag. Therefore, information can be simply and reliably read/written from/to the non-contact IC tag from either of the two sides (or four sides) of the planar rectangular pallet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view showing a pallet according to an embodiment of the present invention. FIG. 1B is a center vertical cross-sectional view thereof FIG. 1C is a horizontal cross-sectional view thereof.

FIG. 2A is a front view showing a pallet according to another embodiment of the present invention. FIG. 2B is a center vertical cross-sectional view thereof. FIG. 2C is a horizontal cross-sectional view thereof.

FIG. 3A is a front view showing a pallet according to still another embodiment of the present invention. FIG. 3B is a center vertical cross-sectional view thereof. FIG. 3C is a horizontal cross-sectional view thereof.

FIG. 4A is a front view showing a pallet according to still another embodiment of the present invention. FIG. 4B is a center vertical cross-sectional view thereof. FIG. 4C is a horizontal cross-sectional view thereof.

FIG. 5A is a front view showing a pallet according to still another embodiment of the present invention. FIG. 5B is a center vertical cross-sectional view thereof. FIG. 5C is a horizontal cross-sectional view thereof.

FIG. 6A is a front view showing a pallet according to still another embodiment of the present invention. FIG. 6B is a center vertical cross-sectional view thereof. FIG. 6C is a horizontal cross-sectional view thereof.

FIG. 7 is a perspective view of the pallet of the embodiment of FIGS. 6A to 6C.

FIG. 8 is a perspective view showing a stack of the pallets of the embodiment of FIGS. 6A to 6C.

FIG. 9A is a front view of a forklift. FIG. 9B is a side view thereof.

FIG. 10 is a block diagram showing a basic structure of an RFID system.

FIG. 11 is a conceptual diagram showing an exemplary pallet management system according to an embodiment of the present invention.

FIG. 12 is a flowchart showing an exemplary pallet management system using the pallet of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to accompanying drawings.

Embodiment 1

FIG. 1A is a front view showing a pallet according to an embodiment of the present invention. FIG. 1B is a center vertical cross-sectional view thereof FIG. 1C is a horizontal cross-sectional view thereof

A pallet 1 shown in these figures is a resin molded product in the shape of a planar rectangle. The pallet 1 is provided with fork entries 2, 2, to admit two forks 101, 101 of a forklift 100 (see FIGS. 9A, 9B). The fork entries 2, 2 are provided on two sides (two opposite sides of the rectangle) 1 a, 1 b of the pallet 1. The forks can be inserted into the pallet 1 in two directions (two-way entry type). The fork entries 2, 2 are located bilaterally symmetrically with respect to a center (a center in a width direction) of the pallet 1.

The pallet 1 is provided with a through hole 3 which extends along the center of the pallet 1 and is located between the fork entries 2, 2. The through hole 3 penetrates through the two sides 1 a, 1 b on which the fork entries 2, 2 are provided.

The through hole 3 has a rectangular cross section. A cross-section area of the through hole 3 is gradually increased toward the sides 1 a, 1 b at both ends of the through hole 3. An inner surface of the through hole 3 is covered with a conductive material, such as a metal or the like. An RFID tag 4 is attached inside the through hole 3. The RFID tag 4 is provided in a vicinity of a middle portion in a length direction of the through hole 3. It should be noted that information about products/goods to be transported on the pallet 1, identification information (e.g., a pallet size, a type number, a pallet ID, etc.), and the like are recorded into the RFID tag 4.

In the pallet 1 of this embodiment, the through hole 3 provided between the fork entries 2, 2 is a kind of transmission pathway to the RFID tag 4. A read signal or a rewrite signal, which is transmitted by an antenna 50 of an RFID interrogator 5 (see FIGS. 9A, 9B) attached to a forklift, is propagated and transferred through the through hole 3 to the RFID tag 4.

As described above, the RFID tag 4 is provided in the vicinity of the middle portion in the length direction of the through hole 3. Therefore, no matter whether the fork 101 of the forklift 100 is inserted into the pallet 1 from the side 1 a or the side 1 b, information stored in the RFID tag 4 attached inside the through hole 3 can be read unbiasedly and reliably. Also, information can be reliably rewritten.

It should be noted that the RFID tag 4 may be attached to either of the lateral surfaces and the top and bottom surfaces inside the through hole 3. The RFID tag 4 may be placed at any position in the length direction of the through hole 3. However, considering the above-described purpose that information stored in the RFID tag 4 can be read unbiasedly and reliably from either of the two sides 1 a, 1 b, it is preferable that the RFID tag 4 is attached in the vicinity of the middle portion in the length direction of the through hole 3.

Now, an exemplary method for reading/writing information from/to the RFID tag 4 attached to the pallet 1 will be briefly described. For example, as shown in FIGS. 9A and 9B, the antenna 50 of the RFID interrogator 5 is attached in a vicinity of a root of the fork 101 of the forklift 100. In this case, when the fork 101 of the forklift 100 is inserted into the fork entry 2 of the pallet 1, information can be read/rewritten from/to the RFID tag 4 on the pallet 1.

The antenna 50 of the RFID interrogator 5 may be attached to an upper portion of a support bearing the fork 101 of the forklift 100. In the case where a plurality of pallets 1, . . . , 1 are stacked when not in use, information can be read/rewritten from/to the RFID tag 4 of each pallet 1 by lifting the pallets 1, . . . , 1 together with the fork 101 of the forklift 100.

When an empty pallet 1 is placed in a pallet storage site, information stored in the RFID tag 4 may be read using the antenna of an RFID interrogator provided in the pallet storage site. As a result, identification information can be read from the empty pallet 1, so that the availability of the pallet 1 can be managed.

Next, examples of specific numerical values of the through hole 3 will be described.

In the case of the pallet 1 of FIGS. 1A to 1C, the cross-section of the through hole 3 is a rectangle. Therefore, either of the sides of the rectangle needs to have a length of λ/2 or more (λ: the wavelength of a frequency used by an RFID interrogator). The reason will be described below.

Rectangular waveguides (with a rectangular cross-section) have the transmission characteristics of a HPF (high pass filter which passes frequencies higher than a predetermined frequency (fo)). In other words, rectangular waveguides have a property of not transmitting frequencies lower than fo. In the case of rectangular waveguides, the frequency fo is determined by the length L of a side of the rectangular waveguide as follows. fo*λ=C(C: speed of light) L=λ/2

In the embodiment of FIGS. 1A to 1C, the through hole 3 of the pallet 1 corresponds to a rectangular waveguide. When a frequency used by RFID is 2.45 GHz, a dimension (lateral width) of the through hole 3 needs to be broader than about 61.2 mm in order to transmit the frequency through the through hole 3 and read the tag information of the RFID tag 4 attached inside the through hole 3.

Therefore, for example, when a frequency of 2.45 GHz is used, any one of the sides of the through hole 3 needs to be equal to or larger than about 62 mm in order to transmit a read signal or a rewrite signal of RFID through the inside of the through hole 3 of the pallet 1.

Embodiment 2

FIG. 2A is a front view of a pallet according to another embodiment of the present invention. FIG. 2B is a center vertical cross-sectional view thereof. FIG. 2C is a horizontal cross-sectional view thereof.

FIGS. 2A to 2C show a pallet 11, which is a resin molded product in the shape of a planar rectangle. The pallet 11 is provided with fork entries 12, 12 to admit the two forks 101, 101 of the forklift 100 (see FIGS. 9A, 9B) on each of four sides 11 a, 11 b, 11 c, 11 d thereof. The forks can be inserted into the pallet 11 in four directions (four-way entry type).

The fork entries 12, 12, which are provided on the sides 11 a, 11 b of the pallet 11, are located symmetrically with respect to a center (a center in a width direction) of the pallet 11. The fork entries 12, 12, which are provided on the sides 11 c, 11 d of the pallet 11, are located symmetrically with respect to a center (a center in a length direction) of the pallet 11.

The pallet 11 is provided with two through holes 13, 13, each of which extends along the center of the pallet 11. These two through holes 13, 13 intersect orthogonally and are each disposed between the fork entries 12, 12. The through holes 13 penetrate through the two sides 11 a, 11 b and the two sides 11 c, 11 d, respectively, on each of which the fork entries 12 are provided.

Each through hole 13 has a rectangular cross-section. A cross-section area of each through hole 13 is gradually increased toward the sides 11 a, 11 b or 11 c, 11 d at both ends of the through hole 13. An inner surface of each through hole 13, 13 is covered with a conductive material, such as a metal or the like. An RFID tag 4 is attached inside the through holes 13, 13. The RFID tag 4 is provided in a vicinity of a middle portion in a length direction of each through holes 13, 13.

In the pallet 11 of this embodiment, each of the two through holes 13, 13 is a kind of transmission pathway to the RFID tag 4. A read signal or a rewrite signal, which is transmitted by the antenna 50 of the RFID interrogator 5 (see FIGS. 9A, 9B) attached to a forklift, is propagated and transferred through any one of the two through holes 13, 13 to the RFID tag 4.

As described above, the RFID tag 4 is provided in the vicinity of the middle portion in the length direction of each through holes 13, 13. Therefore, no matter whether the fork 101 of the forklift 100 is inserted into the pallet 11 from the side 11 a, 11 b, 11 c or 11 d, information stored in the RFID tag 4 attached inside the through holes 13, 13 can be read unbiasedly and reliably. Also, information can be reliably rewritten.

It should be noted that the RFID tag 4 may be attached to either of the lateral surfaces and the top and bottom surfaces inside the through holes 13, 13. The RFID tag 4 may be placed at any position in the length direction of the through holes 13, 13. However, considering the above-described purpose that information stored in the RFID tag 4 can be read and rewritten unbiasedly and reliably from any of the four sides 11 a, 11 b, 11 c and 11 d of the pallet 11, it is preferable that the RFID tag 4 is attached in the vicinity of the middle portion in the length direction of the through holes 13, 13.

Also in Embodiment 2, the through hole 13 has a rectangular cross-section. For the same reason as described in Embodiment 1, either of the sides of the through hole 13 needs to have a length of λ/2 or more (λ: the wavelength of a frequency used by an RFID interrogator). For example, when a frequency of 2.45 GHz is used, the length of either of the sides of the through hole 13 needs to be equal to or larger than about 62 mm in order to transmit a read signal or a rewrite signal of the RFID through the inside of the through hole 13 of the pallet 11.

Embodiment 3

FIG. 3A is a front view of a pallet according to still another embodiment of the present invention. FIG. 3B is a center vertical cross-sectional view thereof. FIG. 3C is a horizontal cross-sectional view thereof.

A pallet 21 shown in FIGS. 3A to 3C is characterized in that a through hole 23 having a circular cross-section is provided between fork entries 2, 2. The other structure is basically the same as the embodiment of FIGS. 1A to 1C.

The pallet 21 is provided with a through hole 23 which extends along a center of the pallet 21 and penetrates through two sides 1 a, 1 b of the pallet 21. A cross-section area of the through hole 23 is gradually increased toward the sides 1 a, 1 b at both ends of the through hole 23. An inner surface of the through hole 23 is covered with a conductive material, such as a metal or the like.

In the pallet 21 of FIGS. 3A to 3C, the through hole 23 has a circular cross-section. The radius of the through hole 23 needs to be equal to or larger than λ/3.4 (λ: the wavelength of a frequency used by an RFID interrogator). The reason will be described below.

Similar to rectangular waveguides, circular waveguides (with circular cross-section) have the transmission characteristics of a HPF (high pass filter which passes frequencies higher than a predetermined frequency (fo)). In the case of circular waveguides, a Bessel function is involved in calculation of the frequency fo, and therefore, the calculation is complex. However, the frequency fo is determined based on the radius r of a circular waveguide, and the relationship between them is expressed as follows. fo*λ=C (C: speed of light) r=λ/3.4

In the embodiment of FIGS. 3A to 3C, the through hole 23 of the pallet 21 corresponds to a circular waveguide. When a frequency used by RFID is 2.45 GHz, the radius r of the through hole 23 needs to be larger than about 36.0 mm in order to transmit the frequency through the through hole 23 and read tag information of an RFID tag 4 attached inside the through hole 23.

Embodiment 4

FIG. 4A is a front view of a pallet according to still another embodiment of the present invention. FIG. 4B is a center vertical cross-sectional view thereof. FIG. 4C is a horizontal cross-sectional view thereof.

A pallet 71 shown in FIGS. 4A to 4C is characterized in that a through hole 73 having a cross-section in the shape of a ridge is provided between fork entries 2, 2. The other structure is basically the same as the embodiment of FIGS. 1A to 1C.

The pallet 71 is provided with the through hole 73 which extends along a center of the pallet 71 and penetrates through two sides 1 a, 1 b of the pallet 71. An inner surface of the through hole 73 is covered with a conductive material, such as a metal or the like. As with the through hole 3 of FIGS. 1A to 1C, a cross-section area of the through hole 73 is gradually increased toward the sides 1 a, 1 b at both ends of the through hole 73.

As described above, in the pallet 1 of Embodiment 1, when a frequency of, for example, 2.45 GHz is used, the length of either side of the through hole 3 needs to be equal to or larger than about 62 mm in order to transmit a read signal or a rewrite signal of RFID through the inside of the through hole 3. In the case of the pallet 71 of FIGS. 4A to 4C, the length of either side of the through hole 73 can be equal to or smaller than about 62 mm since the through hole 73 has a ridge-shaped cross-section. The reason will be described below.

Ridge waveguides, such as the through hole 73 having a ridge-shaped cross-section of FIGS. 4A to 4C, can have a considerably low cutoff frequency than rectangular waveguides having the same length and width dimensions. In other words, when the same frequency is used, a ridge waveguide can have smaller length and width dimensions than those of a rectangular waveguide. Therefore, if a through hole 73 having a ridge-shaped cross-section of FIGS. 4A to 4C is used, when a frequency used by RFID is 2.45 GHz, the length of either side of the through hole 73 can be equal to or smaller than about 62 mm so that a read signal or a rewrite signal of the RFID can be transmitted through the inside of the through hole 73 and tag information of an RFID tag 4 attached inside the through hole 73 can be read. The ridge-shaped cross-section of the through hole is not only a “concave” shape as shown in FIGS. 4A to 4C (vertical cross-section, the through hole 73), but also can be, for example, an “H” shape as shown in FIGS. 6A to 5C (vertical cross-section, a through hole 83).

Embodiment 5

FIG. 6A is a front view of a pallet according to still another embodiment of the present invention. FIG. 6B is a center vertical cross-sectional view thereof. FIG. 6C is a horizontal cross-sectional view thereof. FIG. 7 is a perspective view of the pallet of FIGS. 6A to 6C.

The pallet 31 of FIGS. 6A to 6C and FIG. 7 is provided with a through hole 3, which penetrates through two sides 1 a, 1 b of the pallet 31, and a vertical through hole 33, which extends between the top and bottom decks of the pallet 31. The vertical through hole 33 is provided in a vicinity of a middle portion of the planar rectangular pallet 31. The pallet 31 is characterized in that an RFID tag 4 is attached in a vicinity of a middle portion of both the vertical through hole 33 and the through hole 3 between fork entries 2, 2. The other structure is basically the same as in the embodiment of FIGS. 1A to 1C.

In the case of the pallet 31 of this embodiment, when the empty pallets 31 are stacked in a pallet storage site, the middle portions of the vertical through holes 33, . . . , 33 are sequentially aligned as shown in FIG. 8. As a result, a through hole which vertically penetrates the middle portions of the pallets 31 is formed. This through hole plays a role as a kind of transmission pathway, as with the through hole 3 provided between the fork entries 2, 2. In this case, for example, by providing a planar antenna of an RFID interrogator on a bottom surface of the pallet storage site, it is possible to read information stored in the RFID tag 4 of each of the stacked pallets (empty pallets) 31, . . . , 31 simultaneously. Also, information can be rewritten simultaneously.

When a plurality of empty pallets 31, . . . , 31 are transported together by the forklift 100, the antenna 50 of the RFID interrogator 5 provided on the forklift 100 (see FIG. 9A, 9B) can be used to read/write information from/to the RFID tag 4 of each of the stacked empty pallet 31, . . . , 31. For example, pallets can be managed in real time when the pallets are lent or returned to/from a hirer.

Further, by transferring the read information to, for example, a management center, the inventory of empty pallets can be managed centrally, leading to an improvement in the utilization rate of pallets.

As described above, empty pallets can be easily managed, thereby also preventing loss and outflow of pallets.

In the case of the pallet 31 of this embodiment, the vertical through hole 33 is provided at the middle portion thereof. Therefore, when the RFID tag 4 attached to the pallet 31 needs to be exchanged due to a defect, malfunction or the like, the RFID tag 4 can be exchanged by utilizing the vertical through hole 33.

If the vertical through hole 33 provided on the middle portion of the pallet 31 has a circular cross-section as shown in FIGS. 6A to 6C and FIG. 7, the radius of the vertical through hole 33 should be equal to or larger than λ/3.4 (λ: the wavelength of a frequency used by an RFID interrogator). For example, when the frequency used by the RFID is 2.45 GHz, the radius r of the vertical through hole 33 is larger than about 36.0 mm.

If the vertical through hole has a rectangular cross-section, the length of either side of the through hole having the rectangular cross-section should be equal to or larger than λ/2 (λ: the wavelength of a frequency used by an RFID interrogator). For example, when the frequency used by the RFID is 2.45 GHz, the length of either side of the vertical through hole should be equal to or larger than about 62 mm.

The pallets according to the embodiments of the present invention may be made of either wood or synthetic resin. Pallets made of synthetic resin are preferable since synthetic resin is easy to shape.

The pallets according to the embodiments of the present invention may be either of the two-way entry type, in which the pallet is provided with fork entries to admit two forks of a forklift on two sides thereof and the forks can be inserted into the pallet in two directions, or of the four-way entry type, in which the pallet is provided with fork entries on all sides (four sides) thereof and the forks can be inserted into the pallet in four directions.

Hereinafter, an exemplary pallet management system in which a pallet of the present invention is used as a rental pallet will be described below.

In this example, the pallet 31 of FIGS. 6A to 6C and FIG. 7 is used. It is assumed that identification information, such as a pallet size, a type number, a pallet ID and the like, are stored in the RFID tag 4 attached to the pallet 31. It is also assumed that the forklift 100 is equipped with the RFID interrogator 5 and its antenna 50 as shown in FIGS. 9A, 9B and a transceiver 6. It should be noted that the antenna 50 of the RFID interrogator 5 is attached in the vicinity of the root of the fork 101 of the forklift 100.

A basic structure of an RFID system used for management of pallets will be described with reference to FIG. 10.

The RFID system of FIG. 10 comprises the above-described RFID interrogator 5 and its antenna 50 mounted on the forklift 100, the above-described RFID tag 4 and its antenna 40 attached to the pallet 31, and the like.

The RFID interrogator 5 comprises a transmission section 51 for interrogation, a reception section 52 for reading, a transmission section 53 for writing, a control section 54, and the like. The RFID tag 4 comprises a modulation/demodulation section 41, a modulated signal generating section 42, a demodulation section 43, an information memory section 44, and the like. The RFID interrogator 5 and the RFID tag 4 communicate with each other via the respective antennas 50 and 40.

This RFID system is operated as follows. The fork 101 of the forklift 100 is inserted into the fork entry 2 of the pallet 31. The antenna 40 of the RFID tag 4 is caused to substantially face the antenna 50 of the RFID interrogator 5. The RFID interrogator 5 transmits a control signal and a non-modulated carrier from the antenna 50 toward the RFID tag 4. The RFID tag 4 receives the radio signal from the RFID interrogator 5 via the antenna 40, and decodes the received control signal to know a data read operation. Data such as an ID number, a pallet number, a hirer and the like are retrieved from the information memory section 44 stored in the RFID tag 4 and the data retrieved from the information memory section 44 is modulated with the received non-modulated carrier. The resultant signal is transmitted (reflected) toward the RFID interrogator 5. The reception section 52 (for reading) of the RFID interrogator 5 receives and demodulates the signal transmitted (reflected) from the RFID tag 4 to obtain desired data. The RFID interrogator 5 also transmits information to be written from the transmission section 53 (for writing) toward the RFID tag 4. This transmitted information is demodulated by the demodulation section 43 of the RFID tag 4 and is then accumulated (written) into the information memory section 44.

RFID systems usually use frequency bands of 125 KHz, 13.56 MHz, 2.45 GHz and the like. Unless a radio set (transceiver) uses the same frequency band as that of the RFID system, the RFID system and the radio set can be operated independently with respect to time. When the frequency of 2.45 GHz is used for both the RFID system and the radio set, it is generally preferable that the RFID system and the radio set are controlled not to perform simultaneous transmission to avoid radio interference.

A specific exemplary system for managing rental pallets will be described with reference to FIG. 11.

In this management system, it is assumed that a host terminal 201 is managed by a rental pallet company.

The host terminal 201 possesses a database of lending information (e.g., information about a hirer of rental pallets, information about an entity which returns pallets, a rental period, the number of rental pallets, etc.) and pallet-specific information possessed by a rental pallet company (e.g., a pallet size, a type number, a pallet ID, etc.).

Rental information is, for example, handled as follows. Customers who want to hire pallets contact a rental pallet company by telephone or the like. The contents of the customer's rental order are input by the rental pallet company. Alternatively, customers access a website run by a rental pallet company via the Internet or the like and input the contents of their rental order on a display screen by themselves. The contents of the orders are accumulated.

The pallet specific information is the whole or a part of information possessed by a rental pallet company. It is assumed that a unique number or symbol is assigned as a pallet ID to each pallet. For example, pallet IDs are assigned to newly purchased or produced pallets and are registered into a master database.

A radio set base station 202 is connected to the host terminal 201 and has a control section (not shown) for transmitting and receiving various information. The radio set base station 202 transmits information stored in the host terminal 201 to a transceiver 6 described elsewhere herein, and receives various information about a pallet which is transmitted from the transceiver 6.

A forklift 100 comprises two forks (fork portions) 101, 101 for lifting a pallet 31 as shown in FIGS. 9A, 9B. A control section (not shown) of the transceiver 6 is provided in a driver's seat of the forklift 100 so that a driver can manipulate the control section. Also, an RFID interrogator 5 and an antenna 50 thereof are provided in a vicinity of the middle of a root portion of the fork 101 of the forklift 100 (in a vicinity of the middle between the two forks 101, 101). Therefore, when the fork 101 of the forklift 100 is inserted into the fork entry 2 of the pallet 31, information can be read/written from/to the RFID tag 4 attached to the pallet 31. The transceiver 6 transmits various information about a pallet to the radio set base station 202.

When the fork 101 is inserted into the fork entry 2 of the pallet 31 in order for the forklift 100 to transport the pallet 31, information such as the current date, the location (depot) of the forklift 100, and the like can be written into the RFID tag 4 of the pallet 31 via the antenna 50 of the RFID interrogator 5. Also, information about a pallet hirer or information about an entity which returns pallets can be read from the RFID tag 4 of the pallet 31.

Next, a method for managing the inventory, distribution status and collection status of rental pallets will be described with reference to FIG. 12.

Firstly, an exemplary rental system will be described, in which the same pallet that is lent is returned and a rental fee is paid later.

Step S1: the contents of a customer's rental order for a pallet(s) are stored as lending information into the host terminal 201. The contents of a rental order include, for example, hirer: company A, type number: T 11 pallet, desired number of pallets: 10, desired date: June, 1, 12 o'clock, desired period: 10 days, and the like.

Step S2: when the pallet 31 to be lent is transported (e.g., the fork 101 of the forklift 100 is inserted into the fork entry 2 of the pallet 31), the RFID interrogator 5 of the forklift 100 reads an ID number and the like stored in the RFID tag 4 of the pallet 31. The RFID interrogator 5 of the forklift 100 can also write lending information and the date of lending into the RFID tag 4 of the pallet 31.

Step S3: the transceiver 6 connected to the RFID interrogator 5 of the forklift 100 transmits the pallet ID, which has been read using the RFID interrogator 5, to the radio set base station 202.

Step S4: the pallet ID transmitted to the radio set base station 202 is stored into the host terminal 201.

Step S5: when the pallet 31 is returned (e.g., the fork 101 of a forklift 100 is inserted into the fork entry 2 of the returned pallet 31) at a location (depot), an RFID interrogator 5 of the forklift 100 reads the pallet ID stored in the RFID tag 4 of the pallet 31.

Step S6: a transceiver 6 connected to the RFID interrogator 5 of the forklift 100 transmits the pallet ID, which has been read by the RFID interrogator 5, to the radio set base station 202.

Step S7: the pallet ID transmitted by the radio set base station 202 is stored into the host terminal 201.

Step S8: the host terminal 201 compares the lending information of each pallet ID in its own database with the collected pallet ID.

Step S9: the host terminal 201 calculates a pallet rental fee based on a pallet size, a type number, the number of pallets, the date of lending and the date of collection.

With the above-described steps, the rental pallet company can read the pallet ID number of each pallet when a forklift moves (transports) the pallet (e.g., the fork of the forklift is inserted into the pallet). The rental pallet company can also write location information about a collection location (depot) and information about the date of collection when the fork of a forklift is inserted into the collected pallet. As a result, it is possible to know the distribution pathway and collection pathway of each pallet, so that the inventory, distribution status and collection status of rental pallets can be managed in association with the actual movement (transportation) of the pallets.

Further, for example, when a program for a pallet rental fee system is previously stored in the host terminal 201, a temporally accurate and meticulous fee system can be constructed.

Next, an exemplary rental system will be described, in which the same pallet that is lent is returned and a rental fee is paid in advance.

In this example, it is assumed that a customer paid to a rental pallet company in advance a rental fee, the amount of which depends on the contents of the customer's rental order. It should be note that steps S1 to S8 of this example are the same as those in the above-described example in which a rental fee is paid later and will not be explained. Only a portion of this example which is different from the above-described example will be described below.

From the above-described step S8, the process goes to subsequent step S10 or S11.

Step S10: when the result of comparison in the host terminal 201 in step S8 shows that a rental pallet is returned to a location (depot) before completion of the rental period of the pallet, the balance of the rental fee to be refunded to the customer is calculated. The refund may be prorated per diem for the rental fee originally paid. Alternatively, the refund may be calculated based on a rate defined for a predetermined period (e.g., on a weekly basis).

Step S11: when a rental pallet is returned to a location (depot) after completion of the rental period of the pallet, the balance of the rental fee to be additionally collected from the customer is calculated.

As described above, the pallets according to the above-described embodiments of the present invention can be effectively used in, for example, a pallet management system which manages the inventory, distribution status, collection status and the like of rental pallets. In such a pallet management system, a non-contact IC tag (e.g., an RFID tag, etc.) is attached to a pallet, and therefore, the moving pathway of the pallet can be directly tracked, thereby making it possible to reduce the effort to input data into a hand-written slip or a computer. Further, the distribution of pallets can be correctly tracked, thereby making it possible to clear the reason for loss or unauthorized use of a pallet. Furthermore, since a person in charge of a distribution stage can be identified, it is possible to, for example, demand an unpaid fee or claim damage due to loss or unauthorized use of pallets.

The present invention can be embodied and practiced in other different forms without departing from the spirit and essential characteristics thereof Therefore, the above-described embodiments are considered in all respects as illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All variations and modifications falling within the equivalency range of the appended claims are intended to be embraced therein. 

1. A pallet for transporting goods, wherein the pallet is in the shape of a planar rectangle, the pallet comprising: fork entries to admit two forks of a forklift, the fork entries being provided on two opposite sides of the panel; and a through hole penetrating through the two sides on which the fork entries are provided, the through hole being located between the fork entries, wherein a non-contact IC tag is provided inside the through hole and in a vicinity of a middle portion in a length direction of the through hole.
 2. The pallet according to claim 1, wherein an inner surface of the through hole is covered with a conductive material.
 3. The pallet according to claim 1 or 2, wherein a vertical cross-section of the through hole has a rectangular shape, and a length of either side of the rectangular through hole is equal to or larger than λ/2 where λ represents a wavelength of a frequency used between the non-contact IC tag and an interrogator.
 4. The pallet according to claim 1 or 2, wherein a vertical cross-section of the through hole has a circular shape, and a radius of the circular through hole is equal to or larger than λ/3.4 where λ represents a wavelength of a frequency used between the non-contact IC tag and an interrogator.
 5. The pallet according to claim 1 or 2, wherein a vertical cross-section of the through hole is in the shape of a ridge.
 6. The pallet according to claim 1 or 2, wherein a cross-section area of the through hole is increased from an inner portion of the pallet toward the sides of the pallet.
 7. The pallet according to claim 1 or 2, wherein a through hole is provided in a vicinity of a middle portion of the pallet, and the through hole intersects with the through hole penetrating through the sides and extends vertically with respect to the pallet.
 8. The pallet according to claim 3, wherein a cross-section area of the through hole is increased from an inner portion of the pallet toward the sides of the pallet.
 9. The pallet according to claim 4, wherein a cross-section area of the through hole is increased from an inner portion of the pallet toward the sides of the pallet.
 10. The pallet according to claim 5, wherein a cross-section area of the through hole is increased from an inner portion of the pallet toward the sides of the pallet.
 11. The pallet according to claim 3, wherein a through hole is provided in a vicinity of a middle portion of the pallet, and the through hole intersects with the through hole penetrating through the sides and extends vertically with respect to the pallet.
 12. The pallet according to claim 4, wherein a through hole is provided in a vicinity of a middle portion of the pallet, and the through hole intersects with the through hole penetrating through the sides and extends vertically with respect to the pallet.
 13. The pallet according to claim 5, wherein a through hole is provided in a vicinity of a middle portion of the pallet, and the through hole intersects with the through hole penetrating through the sides and extends vertically with respect to the pallet.
 14. The pallet according to claim 6, wherein a through hole is provided in a vicinity of a middle portion of the pallet, and the through hole intersects with the through hole penetrating through the sides and extends vertically with respect to the pallet. 